25.11. Sample Counting

Occlusion queries use query pool entries to track the number of samples that
pass all the per-fragment tests. The mechanism of collecting an occlusion
query value is described in Occlusion Queries.

The occlusion query sample counter increments by one for each sample with a
coverage value of 1 in each fragment that survives all the per-fragment
tests, including scissor, sample mask, alpha to coverage, stencil, and depth
tests.